JP3874613B2 - Foundation pile - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cast iron foundation pile having a spiral blade formed at one end.
[0002]
[Prior art]
As a metal foundation pile having a spiral blade formed at the tip, for example, a foundation pile disclosed in Japanese Patent Publication No. 02-62648, Japanese Patent Laid-Open No. 9-324420, Japanese Patent Laid-Open No. 11-269875 is known. It has been.
[0003]
[Problems to be solved by the invention]
Among the above, the “steel pipe pile” described in Japanese Examined Patent Publication No. 02-62648 has a spiral blade (spiral wing) on the outer periphery of the bottomed pipe end, and a drilling blade projects in the axial direction of the steel pipe. Although it was a steel pipe pile installed, the spiral blades and bottom plate were attached to the pipe end of the metal pipe by welding, so there was a disadvantage that it was expensive.
[0004]
Moreover, since the steel pipe pile described in this publication has a bottom, there is a problem that the bottom plate becomes a resistance and it is difficult to dig.
Furthermore, the spiral blade that exerts the forward force when digging into the ground is made by processing a veneer into a spiral shape and welding it to a steel pipe with a certain thickness. There was also a problem that the strength of the blade itself and the attachment strength to the steel pipe as a pile were not sufficient, and the load supporting strength of the spiral blade was not sufficient after being buried in the ground as a foundation pile.
[0005]
In addition, the “screw-in type steel pipe pile” disclosed in Japanese Patent Laid-Open No. 9-324420 has a helical plate attached to the lower surface of the tip portion of the steel pipe by welding means. There is a disadvantage that the work is required and the production takes time, and the cost is increased accordingly.
[0006]
In addition, since there is no excavation blade at the tip of the steel pipe pile, there is a problem that the excavation efficiency is poor because it is necessary to rely only on the screw advance force of the spiral strip to dig into the ground.
The “rotary buried open-ended pile” disclosed in Japanese Patent Laid-Open No. 11-269875 has an opening at the tip of the tubular pile, so there are few problems such as difficulty in digging like all the two, but the spiral blade is Since it is attached to the outer periphery of the end of the steel pipe by welding, there is a problem that it takes time for manufacturing and is expensive.
[0007]
An object of the present invention is to solve the above problems, facilitate the manufacture of a foundation pile provided with a spiral blade at one end of a metal tube, and improve the excavation performance.
[0008]
[Means for Solving the Problems]
In the foundation pile of the present invention, the tube end surface of the thick portion of the metal pipe whose one end side is thickened is a spiral surface, and the root portion is thick in the radial direction from the spiral tube end surface. A spiral blade is integrally formed by casting, and a drilling blade projecting in the axial direction is integrally projected from the spiral tube end surface of the metal tube.
[0009]
Therefore, the foundation pile of the present invention has a metal pipe that is a main body and a spiral blade at the tip thereof integrated by casting, so that the pipe body and the spiral blade can be formed at once with a casting mold and manufactured. Becomes easy. In addition, since the thickness of both ends of the pipe and the base of the spiral blade extending in the radial direction is increased, the support strength of the spiral blade that supports the buried foundation pile is increased. The supporting force for the superstructure is large.
[0010]
Furthermore, when excavating, the earth and sand are excavated and softened by the excavating blade at the end face of the pipe, so that the excavation can be easily performed, and the verticality of the pile is improved due to the ease of excavation by the excavating blade.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of the present invention will be described.
FIG. 1 is a partially broken front view of a foundation pile according to an embodiment of the present invention, and FIG. 2 is a partially broken left side view of FIG.
[0012]
In FIG. 1, 1 shows the metal pipe which comprises a pile main body, for example, shows the cast iron pipe manufactured by centrifugal force casting.
One end 1a of the metal tube 1 is made thicker than the wall thickness t of the normal straight tube portion 1b as shown in the figure, and the tube end surface 2 of the thick wall portion 1a is also shown in FIG. Further, the spiral blade 3 is formed integrally by casting so that the spiral surface 3 is further extended in the radial direction from the tube end surface 2 and the thickness of the root portion 3a is larger than the thickness of the radially outer side 3b. Yes.
[0013]
Further, excavating blades 4... 4 are integrally projected from the pipe end surface 2 so as to extend in the axial direction of the metal pipe 1.
The excavating blades 4... 4 may be integrally formed with the metal tube 1 by casting, like the spiral blades 3. However, the block excavating blades 4... 4 are welded to the tube end surface 2 of the metal tube 1. Alternatively, the pipe end face 2 may be formed to protrude from the spiral blade 3 by the height of the block-shaped excavating blade, and the excavating blades 4 and 4 may be cut out after demolding.
[0014]
In the above-described embodiment, the thickness T of the thick portion at the one end 1a is set to be twice to three times the thickness t of the normal straight pipe portion 1b.
By setting it as such thickness, it can be set as the intensity | strength which can bear the severe use conditions at the time of excavation, and the weight of the structure after burial.
[0015]
The extended diameter D of the spiral strip 3 is about 1.5 to 2.5 times the diameter d of the straight pipe portion 1.
If it is less than 1.5 times, the digging force by the spiral strip cannot be obtained sufficiently, and the support force by the spiral blades 3 in the ground after being buried is not sufficient. On the other hand, if it is larger than 2.5 times, the supporting force by the spiral blade 3 in the ground increases, but the resistance to digging becomes large and digging becomes difficult.
[0016]
In addition, the diameter D of the spiral strip 3 in the above numerical range is preferably about 1.9 to 2.2 times that of the straight pipe portion 1b.
Next, the usage method of this foundation pile is demonstrated.
[0017]
A straight pipe 1 having a length of about 4 meters, a diameter of about 120 mm, a thickness of 6 mm, and a thickness T of one end 1a of 16 mm over a length of about 140 mm. The thickness h is 16 mm, the thickness is tapered from there, the outer periphery is a constant thickness of 9 mm from the diameter 194 mm, the spiral blade 3 with an outer diameter of 250 mm, and the pipe end As shown in FIG. 1 to FIG. 3, a foundation pile 1 in which four excavation blades 4.
[0018]
This pile was set up perpendicular to the ground surface and rotated.
When the pile 1 is driven to rotate around its axis, the excavating blades 4 and 4 on the pipe end surface begin to excavate the ground surface. When the spiral blade 3 reaches the ground surface, it begins to bite into the ground and then digs into the ground. I went.
[0019]
In this way, a rotational force was applied around the shaft and the pile was dug into the ground. However, the ground was agitated and weakened by the excavating blades 4 and 4, and the excavation was performed smoothly.
Along with this, the foundation pile 1 also dug into the ground in a substantially vertical state.
[0020]
Since the foundation pile after being buried in the ground was buried with the spiral blade at the tip extended into the ground, it showed sufficient support strength even on soft ground.
[0021]
【The invention's effect】
As described above, in the foundation pile of the present invention, the metal pipe as the main body and the spiral blade at the tip thereof are integrated by casting, so the pipe main body and the spiral blade are at once in a casting mold. It can be formed and is easy to manufacture. In addition, since the thickness of one end side of the pipe and the thickness of the root part of the spiral blade extending in the radial direction are thickened, the spiral strip that supports the foundation pile to which the amount of building material is added after embedding The strength of the blades is increased, and the supporting force in the vertical direction after embedding in the ground is large. At the same time, the portion that does not require strength other than the above can be thinned, so that the mass of the entire foundation pile can be reduced.
[0022]
Further, when excavating, the earth and sand are excavated and softened by the excavating blade on the end face of the pipe, so that the excavation can be easily performed, and the verticality of the pile is improved due to the ease of excavation by the excavating blade.
[Brief description of the drawings]
FIG. 1 is a partially broken front view of a foundation pile according to an embodiment of the present invention.
FIG. 2 is a left side view of FIG.
FIG. 3 is a bottom view of FIG. 1;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Metal pipe 1a Thick tube wall part 2 Spiral pipe end surface 3 Spiral blade | wing 3a Spiral blade | root part 4 Excavation blade

Claims (1)

The tube end surface of the thick portion of the metal tube having a thick wall at one end is formed into a spiral surface, and from the spiral tube end surface, a thick spiral blade with a thick root portion is formed by casting. A foundation pile that is integrally extended and has a drilling blade that protrudes in the axial direction integrally projecting from the spiral tube end surface of the metal tube.

Images